Development and Operational Planning for a Fractured, Gas-Condensate Reservoir With a Thin Oil Column, Szeghalom Field, Hungary

Abstract

Abstract The Szeghalom field contains gas condensate and oil in two faulted, anticlinal structures separated by a saddle. The larger structure has a gas column in excess of 200 m [656 ft] thick which is underlain by a 23-m [75-ft] oil column. The reservoir interval consists of metamorphosed and fractured Precambrian basement rocks which are intermixed and overlain in most areas of the field by basement breccias, which in turn are overlain by sedimentary Miocene sandstones, conglomerates, and carbonates. Reservoir performance was simulated using a three-dimensional, three-phase, compositional, dual-porosity, dual-permeability reservoir simulator. After matching history, the model was used to predict performance under four different operating plans: (1) Natural depletion; (2) Cycling of produced gas; (3) Pressure maintenance by CO2 rich gas injection; and (4) Partial gas storage followed by full gas storage. Conceptual facilities design and cash flow projections were prepared for all prediction cases. All methods of operation were shown to have profit potential, but natural depletion is the clear choice from an economic viewpoint.